1. Field of the Invention
The present invention relates to trays for dispensing materials that are volatile and sensitive to setting by exposure to visible light or actinic radiation. The invention has particular application, for example, in the field of dentistry; however, the invention may also be used in other applications, including medical and surgical applications.
2. Description of Related Art
Photocurable resin composite materials, and related conditioning and bonding materials, are increasingly being used in dental and surgical settings. These materials are often sensitive to premature evaporation or setting by light or actinic radiation.
Therefore, effective use of such materials demands a dispensing apparatus that:                allows for small portions of material to be dispensed efficiently,        resists evaporation of volatile agents in the material being dispensed, and        reduces exposure of the material to light and actinic radiation during intermittent use.        
When used for dental and surgical applications, in particular, a fully sterile environment is important. Therefore, it is important that any such dispensing apparatus be comprised of parts that can be made sterile, for example through radiation or autoclaving, either for single or multiple usages, and in the case of single usage, conveniently replaced, all to fulfill infection control standards.
Conventional dispensing apparatus suffer from a number of disadvantages. They typically hold material in shallow, wide-mouthed wells that expose a large proportion of the material to the environment for evaporation and radiation, risking premature setting of the exposed proportion, such wells being typically shaped as shallow square prisms or shallow cylinders or shallow segments of spheres.
Covers to protect the wells are often difficult to operate, so that users will not cover the wells during short intervals between uses. Wells are prone to spill material, for example into adjacent wells, causing cross-contamination. And conventional dispensing apparatus are often difficult to sterilize because of the materials from which they are made and/or because they are shaped with crannies that trap and hold contaminants. Furthermore, conventional dispensing apparatus don't hold dispensing tools for ready access while safe from cross-contamination.
Accordingly, what is needed is a better way to sterilely dispense compounds that can prematurely set through evaporation or radiation.